Flash drive cannot be formatted

Hello,
I also have that problem, at first i'm tyring to format my flash drive but it says flash drive write-protected (during this time, i could still read the files on that flash drive) then i just try and try until it already says that it could not format the flash drive, when i try to open it, there are no more files in it, i don't care about retrieving the files but i have to format the flash drive so i can use it again, i tried to follow every suggestions mentioned above but it didn't work, anymore suggestions, ummm the brand of my flash drive is kingston,